A US wealth/unrealized gains tax might trigger it, because it would likely create a cascade of forced selling, with the proceeds of sales getting burned as tax revenue for entitlement programs or debt payments rather than reinvested.
I don't think that would happen for the same reason that there are income taxes and yet the government doesn't have every last dollar. Sovereign wealth funds sell assets too.
If you think sovereign wealth funds are communism, someone should tell Alaska.